Brilliant green and methyl violet 2B dyes removal using aluminium sulfate (AS) in single and binary systems

Abstract

This study aims to evaluate the removal of Brilliant Green (BG) and Methyl Violet 2B (MV2B) dyes using aluminum sulfate (AS) in single and binary coagulation-flocculation systems. Several factors were considered in the experimental runs, including AS dosage (5–150 mg/L), initial dye concentration (1–50 mg/L), and pH level (2−10). To improve the effectiveness of AS, some coagulants aid were added to the combined coagulation-flocculation process, including activated carbon (PAC) (0–2 g/L), calcium hydroxide (Ca(OH)2) (0–2 g/L), and polymer (0–0.2 mg/L). According to the experimental results, 60 mg/L of aluminum sulfate was the optimum dose for BG (57.39 %) and MV2B (32.45 %) removal at 30 mg/L of initial dye concentration without pH adjustment. The removal of BG and MV2B was reduced more in the acidic and alkaline solutions (pH levels 2 and 10), which was estimated by 64.8 % (pH 2) and 70.25 % (pH 10) for the BG and 45.35 % (pH 2) and 45.52 % (pH 10) for the MV2B. Moreover, the increase in the initial dye concentration leads to decreased treatment efficiency. The combination of AS with coagulants aid confirmed that the CAP obtained high removal efficiency. Whereas, in the binary system, the results with the different coagulant doses confirmed that the maximum efficiency colour removal was obtained, in the binary system with AS alone at (pH of 5.3 and 30 mg/L of the initial dye concentration of each dye), for two optimum doses, which are 130 mg/L and 25 mg/L for BG and MV2B, respectively. The removal efficiency of BG is more considerable than MV2B. Overall results suggest that the coagulation-flocculation of dyes in binary systems could be considered an effective process with socioeconomic and environmental benefits and can give more efficiency in the presence of another process.